Here's an alternate approach that is very similar to Chris' but simplifies things a bit. In Chris' example, he joins the aggregate step back to the previous step (in effect, creating an LOD calc). I love that approach! But in this case, I think you can avoid the complexity and simply use an aggregate to find the minimum number of days to the first event for each individual. It assumes that the event date is after the created date (which, even in your data, it is not) - but a simple filter in the Clean step removes any cases where the event date comes first.

Now, if you need any of the detail from the records that is lost from the aggregation, then definitely use Chris' approach to join the aggregate back to the the previous step (that has the details)!